CN215597791U

CN215597791U - Coal economizer of hot water boiler

Info

Publication number: CN215597791U
Application number: CN202122421220.XU
Authority: CN
Inventors: 姜英波; 李鑫; 朱东洋; 岳晓娜; 杨森; 张润桐; 刘丹
Original assignee: Harbin Hongguang Boiler General Factory Co ltd
Current assignee: Harbin Hongguang Boiler General Factory Co ltd
Priority date: 2021-10-08
Filing date: 2021-10-08
Publication date: 2022-01-21
Anticipated expiration: 2031-10-08

Abstract

A coal economizer of a hot water boiler relates to the technical field of hot water boilers. The utility model solves the problems that the smoke and the working medium are arranged in a counter-current way and the down pipe outside the boiler is arranged in the existing heating hot water boiler, so that the coal economizer pipe is easy to be subjected to ash deposition and low-temperature corrosion, and the boiler is easy to generate vibration, gasification and overburning phenomena. Two upper support beams which are arranged side by side are arranged between a second-stage economizer and a third-stage economizer of the boiler, two upper collecting boxes which are arranged side by side are horizontally arranged right above the first-stage economizer along the length direction of a tail flue of the hot water boiler, a group of hanging pipes which are arranged in a staggered mode are arranged between each upper collecting box and the first-stage economizer, a middle collecting box is horizontally arranged between the first-stage economizer and the second-stage economizer, and a lower collecting box is horizontally arranged below the third-stage economizer along the length direction of the tail flue of the hot water boiler. The utility model is used for realizing the functions of dust deposition resistance, low-temperature corrosion resistance, vibration resistance, gasification resistance and overburning resistance of the boiler.

Description

Coal economizer of hot water boiler

Technical Field

The utility model relates to the technical field of hot water boilers, in particular to a coal economizer of a hot water boiler.

Background

At present, the flue gas and the working medium are arranged in a countercurrent mode, namely the water flow direction is opposite to the flue gas flowing direction, and a down pipe outside the boiler is arranged, so that the phenomena of ash deposition, low-temperature corrosion and vibration, gasification and overburning of a boiler are easily caused to a coal economizer pipe.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the problems that the existing heating hot water boiler is easy to form ash and corrode at low temperature and the boiler is easy to shake, gasify and over-burn due to the countercurrent arrangement of flue gas and working medium and the arrangement of a down pipe outside the boiler, and further provides a coal economizer of the hot water boiler.

The technical scheme of the utility model is as follows:

a kind of coal economizer of the hot-water boiler, it includes upper header 1, hang the tube 2, the first-stage coal economizer 3, the middle header 4, the second-stage coal economizer 5, the third-stage coal economizer 6, lower header 7 and upper supporting beam 8, the first-stage coal economizer 3, the second-stage coal economizer 5 and the third-stage coal economizer 6 are arranged in the afterbody flue of the hot-water boiler from top to bottom sequentially, there are two upper supporting beams 8 side by side horizontally along the afterbody flue length direction of the hot-water boiler between second-stage coal economizer 5 and the third-stage coal economizer 6, both ends of the said upper supporting beam 8 overlap joint on the hot-water boiler owner, the second-stage coal economizer 5 bottom and upper end surface building in of the upper supporting beam 8, the third-stage coal economizer 6 top and upper supporting beam 8 bottom end surface building in of steel frame; two upper collecting boxes 1 which are arranged side by side are horizontally arranged right above the first-stage economizer 3 along the length direction of a flue at the tail part of the hot water boiler, the upper collecting boxes 1 are fixed on a steel frame at the top of the boiler through a plurality of supporting steel plates, a group of hanging pipes 2 which are arranged in a staggered mode are arranged between each upper collecting box 1 and the first-stage economizer 3, the upper ends of the hanging pipes 2 are connected with water outlets of the upper collecting boxes 1, and the lower ends of the hanging pipes 2 are connected with water inlets of the first-stage economizer 3; the middle collecting box 4 is horizontally arranged between the first-stage coal economizer 3 and the second-stage coal economizer 5 along the length direction of a tail flue of the hot water boiler, the middle collecting box 4 is fixed on a steel frame at the top of the boiler through a plurality of supporting steel plates, the water outlet of the first-stage coal economizer 3 is connected with the water inlet of the middle collecting box 4, the water outlet of the middle collecting box 4 is connected with the water inlet of the second-stage coal economizer 5, and the water outlet of the second-stage coal economizer 5 is connected with the water inlet of the third-stage coal economizer 6; the lower header 7 is horizontally arranged below the third-stage coal economizer 6 along the length direction of a flue at the tail part of the hot water boiler, the lower header 7 is fixed on a steel frame at the top of the boiler through a plurality of supporting steel plates, and a water outlet of the third-stage coal economizer 6 is connected with a water inlet of the lower header 7.

Further, first-level economizer 3 includes that two first strut 9 and multiunit are two around first serpentine tube bank, the multiunit is two around first serpentine tube bank along boiler afterbody flue length direction level and sets up side by side, two first strut 9 set up relatively respectively in the left and right sides that the multiunit was two around first serpentine tube bank, two serpentine tube upper ends in every group is two around first serpentine tube bank are connected with the pipe 2 of hanging of both sides respectively, two serpentine tube lower extremes in every group is two around first serpentine tube bank all are connected with middle header 4 water inlet.

Further, every first strut 9 includes two first band steels 13 and the first fagging of a plurality of, and every group is two to be connected through first fagging between the upper and lower adjacent coiled pipe of first coiled pipe bank, and the upper and lower both ends that the multiunit is two to be connected through two first band steels 13 side by side respectively around first coiled pipe bank.

Further, the second-stage economizer 5 comprises two second support frames 10 and a plurality of groups of double-winding second serpentine tube bundles, the plurality of groups of double-winding second serpentine tube bundles are horizontally arranged side by side along the length direction of a tail flue of the hot water boiler, the two second support frames 10 are respectively and relatively arranged on the left side and the right side of the plurality of groups of double-winding second serpentine tube bundles, and the upper ends of two serpentine tubes in each group of double-winding second serpentine tube bundles are connected with a water outlet of the middle header 4.

Further, every second strut 10 includes second band steel 14 and a plurality of second fagging, and every group is two to be connected through the second fagging between the upper and lower adjacent coiled pipe of second serpentine tube bank, and the multiunit is two to be connected through two second band steel 14 side by side respectively around the upper end of second serpentine tube bank, and the multiunit is two to be connected with the up end of two upper supporting beams 8 respectively around the lower extreme of second serpentine tube bank.

Further, the third-level economizer 6 comprises two third support frames 11 and a plurality of groups of double-winding third serpentine tube bundles, the plurality of groups of double-winding third serpentine tube bundles are horizontally arranged side by side along the length direction of a tail flue of the hot water boiler, the two third support frames 11 are respectively and relatively arranged on the left side and the right side of the plurality of groups of double-winding third serpentine tube bundles, the upper ends of two serpentine tubes in each group of double-winding third serpentine tube bundles are connected with the lower ends of two serpentine tubes in each group of double-winding second serpentine tube bundles of the second-level economizer 5, and the lower ends of the two serpentine tubes in each group of double-winding third serpentine tube bundles are connected with a water inlet of the lower header 7.

Further, every third strut 11 includes third band steel 15 and a plurality of third fagging, and every group is two to be connected through the third fagging between the upper and lower adjacent coiled pipe of third serpentine tube bank, and the lower extreme of multiunit is two to be connected through two third band steel 15 side by side respectively around third serpentine tube bank, and the upper end of multiunit is two to be connected with the lower terminal surface of two upper support beams 8 respectively around third serpentine tube bank.

Further, it still includes a lower supporting beam 12, is equipped with two lower supporting beams 12 side by side along boiler tail flue width direction level between two upper supporting beams 8 and the tertiary economizer 6, the both ends of lower supporting beam 12 overlap joint respectively on boiler main steel frame, and upper end face and the lower end face rigid coupling of lower supporting beam 12 of 8 lower terminal beams of upper support.

Further, the hanging pipes 2 comprise front hanging pipes and rear hanging pipes, and the front hanging pipes and the rear hanging pipes are arranged in a staggered mode.

Further, the front hanging pipe comprises a first bending part, a first straight pipe part and a first arc part which are integrally formed from top to bottom, the first straight pipe part is vertically arranged, the first bending part is inclined backwards, an included angle between the first bending part and the first straight pipe part is alpha, and the alpha is 10-15 degrees; hang the pipe after including from top to bottom integrated into one piece's second bending portion, second straight tube portion and second circular arc portion, the vertical setting of second straight tube portion, the second bending portion slopes forward, and the contained angle between second bending portion and the second straight tube portion is beta, and beta is 10 ~ 15.

Compared with the prior art, the utility model has the following effects:

1. each group of hanging pipes 2 is staggered in two rows, so that the excessive resistance during the circulation of the flue gas is reduced, and if the hanging pipes are arranged in a single row, the flue gas resistance is large;

2. the utility model improves the design of the working medium flow path, and changes the prior arrangement of the flue gas and the working medium in a counter-flow manner into a downstream arrangement. Therefore, the utility model has the advantages that water is fed upwards and discharged downwards, so that potassium, sodium and other ions in the fuel are not easy to adhere to the pipe walls of the first-stage coal economizer and the second-stage coal economizer under the high-temperature smoke environment, and the formation of very hard shell-shaped ash scale similar to cement is avoided;

3. because the boiler is not provided with a special descending tube outside the boiler, all the water in all the heated tubes of the hearth rises. When power is cut off suddenly, the heat on the fire grate makes the water in all heated pipe walls of the hearth continuously rise, and the water of the economizer falls down to form a loop with the network backwater, so that boiler accidents such as vibration, gasification and over-burning of the boiler can be prevented.

Drawings

FIG. 1 is a front view of an economizer of a hot water boiler of the present invention;

FIG. 2 is a top plan view of the intermediate header 4 of the present invention assembled with a plurality of double wound second serpentine tube bundles;

fig. 3 is an enlarged view of a portion of fig. 1 at I.

Detailed Description

The first embodiment is as follows: the embodiment is described by combining fig. 1 to fig. 3, and the economizer of the hot water boiler of the embodiment comprises an upper header 1, a hanging pipe 2, a first-stage economizer 3, a middle header 4, a second-stage economizer 5, a third-stage economizer 6, a lower header 7 and an upper supporting beam 8, wherein the first-stage economizer 3, the second-stage economizer 5 and the third-stage economizer 6 are sequentially arranged in a flue at the tail part of the hot water boiler from top to bottom, two upper supporting beams 8 which are arranged side by side are horizontally arranged between the second-stage economizer 5 and the third-stage economizer 6 along the length direction of the flue at the tail part of the hot water boiler, two ends of each upper supporting beam 8 are lapped on a main steel frame of the hot water boiler, the bottom of the second-stage economizer 5 is fixedly connected with the upper end face of the upper supporting beam 8, and the top of the third-stage economizer 6 is fixedly connected with the lower end face of the upper supporting beam 8; two upper collecting boxes 1 which are arranged side by side are horizontally arranged right above the first-stage economizer 3 along the length direction of a flue at the tail part of the hot water boiler, the upper collecting boxes 1 are fixed on a steel frame at the top of the boiler through a plurality of supporting steel plates, a group of hanging pipes 2 which are arranged in a staggered mode are arranged between each upper collecting box 1 and the first-stage economizer 3, the upper ends of the hanging pipes 2 are connected with water outlets of the upper collecting boxes 1, and the lower ends of the hanging pipes 2 are connected with water inlets of the first-stage economizer 3; the middle collecting box 4 is horizontally arranged between the first-stage coal economizer 3 and the second-stage coal economizer 5 along the length direction of a tail flue of the hot water boiler, the middle collecting box 4 is fixed on a steel frame at the top of the boiler through a plurality of supporting steel plates, the water outlet of the first-stage coal economizer 3 is connected with the water inlet of the middle collecting box 4, the water outlet of the middle collecting box 4 is connected with the water inlet of the second-stage coal economizer 5, and the water outlet of the second-stage coal economizer 5 is connected with the water inlet of the third-stage coal economizer 6; the lower header 7 is horizontally arranged below the third-stage coal economizer 6 along the length direction of a flue at the tail part of the hot water boiler, the lower header 7 is fixed on a steel frame at the top of the boiler through a plurality of supporting steel plates, and a water outlet of the third-stage coal economizer 6 is connected with a water inlet of the lower header 7.

The upper header 1, the middle header 4 and the lower header 7 of the present embodiment are supported by respective supporting seats; the support of the first-stage economizer 3 is transmitted to the upper header 1 through the hanging pipe 2; the weight of the second-stage economizer 5 falls on the support beam 8; the support of the third-stage coal economizer 6 is welded to a support beam 8 through a support frame on the third-stage coal economizer, namely a hanging structure; because the supporting beam 8 is arranged in the flue, ventilation is carried out on two sides, otherwise, the heating intensity is reduced, the ventilation wind speed is controlled to be 2-3m/s, and the surface temperature of the supporting beam 8 is controlled to be below 150 ℃.

The second embodiment is as follows: the first-stage economizer 3 of the present embodiment is described with reference to fig. 1, and includes two first brackets 9 and a plurality of groups of double-wound first serpentine tube bundles, the plurality of groups of double-wound first serpentine tube bundles are horizontally arranged side by side along the length direction of the tail flue of the hot water boiler, the two first brackets 9 are respectively and relatively arranged at the left and right sides of the plurality of groups of double-wound first serpentine tube bundles, the upper ends of two serpentine tubes in each group of double-wound first serpentine tube bundles are respectively connected with the hanging pipes 2 at both sides, and the lower ends of two serpentine tubes in each group of double-wound first serpentine tube bundles are both connected with the water inlet of the middle header 4. So set up, two first strut 9 play fixed multiunit double-wound first snakelike tube bank's purpose, guarantee that the multiunit double-wound first snakelike tube bank forms a whole, avoid taking place to warp. Other components and connections are the same as in the first embodiment.

The group of the double-winding first coiled pipes of the embodiment are arranged in parallel, the material of the coiled pipes in the double-winding first coiled pipe bundle is 20GB3087, and the material of the first support frame 9 is 06Cr19Ni 10; the 06Cr19Ni10 material is used for the purpose of having super high temperature resistance.

The third concrete implementation mode: referring to fig. 1, the first support frame 9 of the present embodiment includes two first flat bars 13 and a plurality of first support plates, wherein adjacent upper and lower serpentine tubes of each group of double-wound first serpentine tube bundles are connected by the first support plates, and upper and lower ends of the groups of double-wound first serpentine tube bundles are respectively connected by two side-by-side first flat bars 13. According to the arrangement, the first supporting plates play a role in fixing all the coiled tubes in each group of the double-wound first coiled tube bundles, so that all the coiled tubes in each group of the double-wound first coiled tube bundles are ensured to form a whole, and deformation is avoided; the two first flat bars 13 serve the purpose of fixing all the double-wound first serpentine bundles, and finally the multiple groups of double-wound first serpentine bundles form a whole. Other compositions and connections are the same as in the first or second embodiments.

The fourth concrete implementation mode: the second-stage economizer 5 of the present embodiment is described with reference to fig. 1 to 3, and includes two second brackets 10 and a plurality of groups of double-wound second serpentine tube bundles, the plurality of groups of double-wound second serpentine tube bundles are horizontally arranged side by side along the length direction of the tail flue of the hot water boiler, the two second brackets 10 are respectively and oppositely arranged at the left and right sides of the plurality of groups of double-wound second serpentine tube bundles, and the upper ends of two serpentine tubes in each group of double-wound second serpentine tube bundles are both connected with the water outlet of the middle header 4. So set up, two second strut 10 play the purpose of fixed multiunit two snakelike tube bundles of winding, guarantee that the multiunit is two to form a whole around second snakelike tube bundle, avoid taking place to warp. Other compositions and connection relationships are the same as in the first, second or third embodiment.

The group of double-winding second serpentine tubes of the embodiment are arranged in parallel, the material of the serpentine tubes in the double-winding second serpentine tube bundle is 20GB3087, and the material of the second support frame 10 is 15 CrMo; the purpose of adopting 15CrMo material is that the material has good high temperature resistance.

The fifth concrete implementation mode: the present embodiment is described with reference to fig. 1 to 3, each second support frame 10 of the present embodiment includes a second flat bar 14 and a plurality of second support plates, each group of double-wound second serpentine tube bundles is connected between adjacent upper and lower serpentine tubes by the second support plates, the upper ends of the multiple groups of double-wound second serpentine tube bundles are connected by two side-by-side second flat bars 14, and the lower ends of the multiple groups of double-wound second serpentine tube bundles are connected with the upper end surfaces of the two upper support beams 8. With the arrangement, the second supporting plates play a role in fixing all the coiled tubes in each group of the double-wound second coiled tube bundles, so that all the coiled tubes in each group of the double-wound second coiled tube bundles are ensured to form a whole, and deformation is avoided; the second flat bar 14 serves the purpose of fixing all the double-wound second serpentine bundles, and finally the multiple groups of double-wound second serpentine bundles form a whole. Other compositions and connection relationships are the same as those in the first, second, third or fourth embodiment.

The sixth specific implementation mode: the third-stage economizer 6 of the present embodiment is described with reference to fig. 1 and 3, and includes two third brackets 11 and multiple groups of double-wound third serpentine tube bundles, the multiple groups of double-wound third serpentine tube bundles are horizontally arranged side by side along the length direction of the tail flue of the hot water boiler, the two third brackets 11 are respectively and relatively arranged at the left and right sides of the multiple groups of double-wound third serpentine tube bundles, the upper ends of two serpentine tubes in each group of double-wound third serpentine tube bundles are connected with the lower ends of two serpentine tubes in each group of double-wound second serpentine tube bundles of the second-stage economizer 5, and the lower ends of two serpentine tubes in each group of double-wound third serpentine tube bundles are connected with the water inlet of the lower header 7. So set up, two third strut 11 play fixed multiunit double-wound third snakelike tube bank's purpose, guarantee that the multiunit double-wound third snakelike tube bank forms a whole, avoid taking place to warp. Other compositions and connection relationships are the same as in the first, second, third, fourth or fifth embodiment.

The group of the double-winding third serpentine tubes of the embodiment are arranged in parallel, the material of the serpentine tubes in the double-winding third serpentine tube bundle is 20GB3087, and the material of the third support frame 11 is Q235B; the material Q235B is adopted, so that the smoke temperature at the position is greatly reduced compared with the smoke temperature at the front two stages, and the smoke temperature is only required to be made of common carbon steel.

The seventh embodiment: the present embodiment is described with reference to fig. 1 and 3, each third support frame 11 of the present embodiment includes a third flat steel 15 and a plurality of third support plates, each group of double-wound third serpentine tube bundles is connected between adjacent upper and lower serpentine tubes by the third support plates, the lower ends of the multiple groups of double-wound third serpentine tube bundles are connected by two side-by-side third flat steels 15, and the upper ends of the multiple groups of double-wound third serpentine tube bundles are connected with the lower end surfaces of the two upper support beams 8. With the arrangement, the third supporting plates play a role in fixing all the coiled tubes in each group of the double-wound third coiled tube bundles, so that all the coiled tubes in each group of the double-wound third coiled tube bundles are ensured to form a whole, and deformation is avoided; and the third flat steel 1 plays the purpose of fixing all 5 double-winding third serpentine tube bundles, and finally, a plurality of groups of double-winding third serpentine tube bundles form a whole. Other compositions and connection relationships are the same as in the first, second, third, fourth, fifth or sixth embodiment.

The specific implementation mode is eight: the embodiment is described by combining fig. 1 and fig. 3, and the embodiment further includes a lower support beam 12, two parallel lower support beams 12 are horizontally arranged between the two upper support beams 8 and the third-stage economizer 6 along the width direction of the flue at the tail of the hot water boiler, two ends of the lower support beam 12 are respectively lapped on the main steel frame of the hot water boiler, and the lower end surface of the upper support beam 8 is fixedly connected with the upper end surface of the lower support beam 12. So set up, two lower supporting beam 12 play the effect of supporting two upper supporting beams 8, and two lower supporting beam 12 are close to the 8 center line side settings of upper supporting beam, and the intensity of reinforcing economizer has improved the life of economizer. Other compositions and connection relationships are the same as those of embodiment one, two, three, four, five, six or seven.

The specific implementation method nine: referring to fig. 1, the hanging pipe 2 of the present embodiment includes a front hanging pipe and a rear hanging pipe, which are arranged in a staggered manner. So set up, every group hangs pipe 2 and makes double staggered arrangement to resistance is too big when reducing the flue gas circulation, if make single row, then causes the flue gas resistance big. Other compositions and connection relationships are the same as those in the first, second, third, fourth, fifth, sixth, seventh or eighth embodiment.

The detailed implementation mode is ten: the embodiment is described with reference to fig. 1, the front hanging tube of the embodiment includes a first bending portion, a first straight tube portion and a first arc portion which are integrally formed from top to bottom, the first straight tube portion is vertically arranged, the first bending portion is inclined backwards, an included angle between the first bending portion and the first straight tube portion is α, and α is 10-15, preferably 10 °; hang the pipe after including from top to bottom integrated into one piece's second bending portion, second straight tube portion and second circular arc portion, the vertical setting of second straight tube portion, the second bending portion inclines forward, and the contained angle between second bending portion and the second straight tube portion is beta, and beta is 10 ~ 15, preferably 10. Other compositions and connections are the same as those of the first, second, third, fourth, fifth, sixth, seventh, eighth or ninth embodiments.

Principle of operation

The operation principle of the economizer of the hot water boiler according to the present invention will be described with reference to fig. 1 to 3:

the utility model is arranged at the tail part of the hot water boiler, and the water circulation mode of the hot water boiler is forced circulation. The return water of the heat supply network enters a small boiler arranged at the top, enters a rear water-cooling wall lower collecting box through six internal down pipes, enters a boiler barrel low-temperature area through a rear water-cooling wall and a condensed slag pipe bundle, is introduced into an upper collecting box 1 through a connecting pipe, enters a middle collecting box 4 through a first-stage economizer 3, then enters a second-stage economizer 5, further enters a third-stage economizer 6, enters a water-cooling wall lower collecting box on two side walls through a

lower collecting box

7 and 12 connecting pipes, introduces a part of the incoming water into a front water-cooling wall lower collecting box through a connecting short pipe, reaches the outlet water temperature after being heated by two sides and a front water-cooling wall pipe, enters the boiler barrel, is led out through a water outlet pipe on the top of the boiler barrel and is sent to the heat supply network.

In order to protect the tail coal economizer from depositing ash shells, the hot water boiler is improved on the design of a working medium flow path, and the traditional mode that the flue gas and the working medium are arranged in a counter-flow mode is changed into a downstream mode. The temperature of the wall of the pipe of the utility model reaches 166 ℃ at the lowest position after the temperature of the working medium is increased, and the temperature exceeds the temperature of the dew point. Can prevent the outer surface of the pipe wall from dewing, acid corrosion and ash adhesion to form an ash shell and reduce the heat transfer performance.

Water flow: circulating water is distributed into two upper collection boxes 1 through 6 groups of pipes phi 133X6 from a boiler barrel, enters a first-stage economizer 3 through a hanging pipe 2, then is converged into a middle collection box 4, and is discharged to enter a second-stage economizer 5 and a third-stage economizer 6 and finally is converged into a lower collection box 7, and the circulating water is guided to the heating surfaces of the water-cooled walls of a hearth by the lower collection box 7 through 12 pipes phi 133X 6.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. An economizer for a hot water boiler, characterized in that: the boiler tail flue gas purification device comprises an upper header (1), a hanging pipe (2), a first-stage economizer (3), a middle header (4), a second-stage economizer (5), a third-stage economizer (6), a lower header (7) and an upper supporting beam (8), wherein the first-stage economizer (3), the second-stage economizer (5) and the third-stage economizer (6) are sequentially arranged in the tail flue of a hot water boiler from top to bottom, two upper supporting beams (8) which are arranged side by side are horizontally arranged between the second-stage economizer (5) and the third-stage economizer (6) along the length direction of the tail flue of the hot water boiler, two ends of each upper supporting beam (8) are lapped on a main steel frame of the hot water boiler, the bottom of the second-stage economizer (5) is fixedly connected with the upper end face of the upper supporting beam (8), and the top of the third-stage economizer (6) is fixedly connected with the lower end face of the upper supporting beam (8); two upper collecting boxes (1) which are arranged side by side are horizontally arranged right above the first-stage economizer (3) along the length direction of a flue at the tail part of the hot water boiler, the upper collecting boxes (1) are fixed on a steel frame at the top of the boiler through a plurality of supporting steel plates, a group of hanging pipes (2) which are arranged in a staggered mode are arranged between each upper collecting box (1) and the first-stage economizer (3), the upper ends of the hanging pipes (2) are connected with water outlets of the upper collecting boxes (1), and the lower ends of the hanging pipes (2) are connected with water inlets of the first-stage economizers (3); the middle collecting box (4) is horizontally arranged between the first-stage economizer (3) and the second-stage economizer (5) along the length direction of a tail flue of the hot water boiler, the middle collecting box (4) is fixed on a steel frame at the top of the boiler through a plurality of supporting steel plates, a water outlet of the first-stage economizer (3) is connected with a water inlet of the middle collecting box (4), a water outlet of the middle collecting box (4) is connected with a water inlet of the second-stage economizer (5), and a water outlet of the second-stage economizer (5) is connected with a water inlet of the third-stage economizer (6); lower header (7) set up in third level economizer (6) below along boiler afterbody flue length direction level, lower header (7) are fixed on boiler top steelframe through many places supporting steel plate, and third level economizer (6) delivery port is connected with lower header (7) water inlet.

2. The economizer of a hot water boiler according to claim 1, wherein: first-level economizer (3) include two first strut (9) and the first snakelike tube bank of multiunit double-winding, the multiunit double-winding first snakelike tube bank sets up side by side along boiler afterbody flue length direction level, two first strut (9) set up the left and right sides that the first snakelike tube bank of multiunit double-winding respectively relatively, every group double-winding two snakelike tube upper ends in the first snakelike tube bank are connected with hanging pipe (2) of both sides respectively, every group double-winding two snakelike tube lower extremes in the first snakelike tube bank all are connected with middle header (4) water inlet.

3. The economizer of a hot water boiler according to claim 2, wherein: every first strut (9) includes two first band steels (13) and the first fagging of a plurality of, and every group is two to be connected through first fagging between the upper and lower adjacent coiled pipe of first coiled pipe bank, and the upper and lower both ends that the multiunit was two to be wound first coiled pipe bank are connected through two first band steels (13) side by side respectively.

4. The economizer of a hot water boiler according to claim 1, wherein: the second-stage economizer (5) comprises two second support frames (10) and a plurality of groups of double-winding second serpentine tube bundles, the plurality of groups of double-winding second serpentine tube bundles are horizontally arranged side by side along the length direction of a tail flue of the hot water boiler, the two second support frames (10) are respectively and relatively arranged on the left side and the right side of the plurality of groups of double-winding second serpentine tube bundles, and the upper ends of two serpentine tubes in each group of double-winding second serpentine tube bundles are connected with a water outlet of the middle header (4).

5. The economizer of a hot water boiler according to claim 4, wherein: every second strut (10) includes second band steel (14) and a plurality of second fagging, and every group is two to be connected through the second fagging between the upper and lower adjacent coiled pipe of second serpentine tube bank, and the multiunit is two to be connected through two second band steel (14) side by side respectively around the upper end of second serpentine tube bank, and the multiunit is two to be connected with the up end of two upper support beams (8) respectively around the lower extreme of second serpentine tube bank.

6. The economizer of a hot water boiler according to claim 1, wherein: the third-level economizer (6) comprises two third support frames (11) and a plurality of groups of double-winding third serpentine tube bundles, the groups of double-winding third serpentine tube bundles are horizontally arranged side by side along the length direction of a tail flue of the hot water boiler, the two third support frames (11) are respectively and relatively arranged at the left side and the right side of the groups of double-winding third serpentine tube bundles, the upper ends of two serpentine tubes in each group of double-winding third serpentine tube bundles are connected with the lower ends of two serpentine tubes in each group of double-winding second serpentine tube bundles of the second-level economizer (5), and the lower ends of two serpentine tubes in each group of double-winding third serpentine tube bundles are connected with a water inlet of the lower header (7).

7. The economizer of a hot water boiler according to claim 6, wherein: every third strut (11) includes third band steel (15) and a plurality of third fagging, and every group is two to be connected through the third fagging between the upper and lower adjacent coiled pipe of third serpentine tube bank, and the lower extreme of multiunit double-wound third serpentine tube bank is connected through two third band steel (15) side by side respectively, and the upper end of multiunit double-wound third serpentine tube bank is connected with the lower terminal surface of two upper supporting beams (8) respectively.

8. The economizer of a hot water boiler according to claim 1, wherein: it still includes supporting beam (12) down, is equipped with two supporting beam (12) side by side along boiler tail flue width direction level between two last supporting beam (8) and third level economizer (6), the both ends of supporting beam (12) overlap joint respectively on boiler main steel frame down, goes up supporting beam (8) lower terminal surface and supporting beam (12) upper end rigid coupling down.

9. The economizer of a hot water boiler according to claim 1, wherein: the hanging pipe (2) comprises a front hanging pipe and a rear hanging pipe, and the front hanging pipe and the rear hanging pipe are arranged in a staggered mode.

10. The economizer of a hot water boiler according to claim 9, wherein: the front hanging pipe comprises a first bending part, a first straight pipe part and a first arc part which are integrally formed from top to bottom, the first straight pipe part is vertically arranged, the first bending part is inclined backwards, an included angle between the first bending part and the first straight pipe part is alpha, and the alpha is 10-15 degrees; hang the pipe after including from top to bottom integrated into one piece's second bending portion, second straight tube portion and second circular arc portion, the vertical setting of second straight tube portion, the second bending portion slopes forward, and the contained angle between second bending portion and the second straight tube portion is beta, and beta is 10 ~ 15.